Joshua L. answered • 08/02/24
Experienced Math and Stats Tutor for All Ages
Hi JB,
Get the regression line equation via a TI-80s series calculator. Enter # of credits enrolled in List L1, Tuition per Semester in L2. Then go to STAT- CALC - 2VarStats - LinReg ax + b:
Equation is:
Y^ = 161.86x + 83.571
where:
x = number of credits per semester
y^ = predicted tuition
Plug 7 in for x:
y^ = 161.86 (7) + 83.571
y^ = $1216.59 for 7-credit semester
You could use the same process for a 7-credit year; just use the per year column as L2.
I hope this helps.
Joshua L.
Not sure how you got those models, but your single-digit model yields the same answer, effectively, as the regression line y = 163 (7) + 75 = 1216. It's extremely complicated to get a regression equation by hand--four step formula that involves squares and sums of squares, Notice, too, that slopes will not be equal for different ordered pairs. For example: m1 = (2031-1053)/ (12-6) = 163 m2 = (2508 - 2031)/ (15-12) = 15908/02/24
J. B.
I tried to find the slope for the first two order pairs (15, 2508)(12, 2031) as that's the context of the assignment to find what the amount for six classes would be But the model doesn't work with single digit classes, to get 7, as need for the question.08/02/24
Joshua L.
Correct. And that’s the reason for regression line equation. I don’t know how to get a viable solution without using regression, but another tutor may. Sorry I couldn’t help more.08/02/24
Mark M.
If the cost of the credits is linear between 6 and 12 credits then the incease is $163 per credit per semester and $326 per year.08/02/24
James S.
08/03/24
Mark M.
Well then what's the kerfuffle?08/03/24
J. B.
The cost doesn't appear linear actually. The formula of y=158x +123 doesn't work for single digits numbers of classes. if you try to get the amount for 12 classes and 15, the formula pans out, but it doesn't for six classes. The slope is different for both.08/03/24
Mark M.
True, yet the question only involves a single digit amount. It is a piece-wise function.08/03/24
J. B.
Thanks, sorry but the context is actually slopes and ordered pair...how would I get that model via slope? I get two different models. Y=158x +123 *for double digit credits* y= 163x + 75 *for single digit credits*08/02/24